Feisty Bowtruckle

Hexproof
At the beginning of combat, you may roll a D20.
If you succeed (11-19), Feisty Bowtruckle gains unblockable until end of turn.
If you roll a critical (20), Feisty Bowtruckle gains unblockable and doubles its power and toughness
until end of turn.
If you finnigan (1), sacrifice Feisty Bowtruckle
instead.